Just How Small Is an Atom?

When it comes to the world beyond our direct, ordinary experience, we just don't have what it takes to understand the differences in scale. If you are given a model Earth and Moon made to scale, for instance, and you're asked to estimate how far apart they would have to be from each other to represent their true distance, most people fail this test miserably. Same thing if you ask people to describe the relationships between the constituent parts making up an atom. So, to help with that problem, here's a quick little lesson on understanding just how small an atom is, and a few other fun facts:

They made things for difficult for themselves than they really had to with that density scenario, didn't they?